2022职称英语(理工类)完形填空樊老师成功押题版.docxVIP

Better Solar Energy Systems:More Heat,More Light That’s an economics problem. Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower cost. And it’s also a real estate problem: photovoltaic cells can take up all the space on the roof, leaving little room for thermal applications. In a pair of studies, Joshua Pearce, an associate professor of materials science and engineering, has devised a solution in the form of a better PVT made with a different kind of silicon. His research collaborators are Kunal Girotra from ThinSilicon in California and Michael Pathak and Stephen Harrison from Queen’s University, Canada. “That means that their efficiency drops when you expose them to light—pretty much the worst possible effect for a solar cell,〞 Pearce explains, which is one of the reasons thin-film solar panels make up only a small fraction of the market. However, Pearce and his team found a way to engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new type of PVT.You don’t have to cool down thin-film silicon to make it work. In fact, Pearce’s group discovered that by heating it to solar-thermal operating temperatures, near the boiling point of water, they could make thicker cells that largely overcame the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy collector, they also found that by spike annealing (baking the cell once a day), they boosted the solar cell’s electrical efficiency by over 10 percent. Sharks Perform a Service for Earths Water It is hard to get people to think of sharks as anything but a deadly enemy. They are thought to attack people frequently. But these fish perform a valuable service for earths waters and for human beings. Yet business and sport fishing are threatening their existence Some sharks are at risk of disappearing from Earth. A shark has an extremely good sense of smell. It can find